Peter Dickinson's three books about the 'Changes', which cause the people of England to turn against machinery and withdraw into a dark age of malicious ignorance, appeared at almost the same time as [John Christopher's 'White Mountains' trilogy]…. Peter Dickinson is even farther from the SF mainstream than John Christopher. In the first book to appear, [The Weathermonger, Geoffrey] and his sister Sally set off through hostile countryside in a splendid antique Rolls-Royce from the Beaulieu motor museum to find the cause of the Changes. This part of the book is a vivid adventure story, and the passages in which the hero practises his mysterious art of conjuring up a different weather are fine and poetic, but the book comes a sorry tumble in the end with its incongruous attribution of the Changes to a revived but drug-sick Merlin. (p. 216)

The second book, Heartsease …, moves back in time...